1. Field
The present disclosure relates to a micro probe and a manufacturing method thereof, and more particularly, to a micro probe and a manufacturing method thereof, which allows the micro probe to be inserted into the brain while maintaining the insertion intensity of the micro probe, and after the probe being inserted into the brain, allows the soluble portion keeping the insertion intensity to be dissolved in the solution in the cranium to expose flexible material, thereby minimizing the damage of neurons of the brain even though the probe is used for a long time.
2. Description of the Related Art
Recent studies are actively made to treat the cerabropathy and investigate operations of the brain by detecting and analyzing cranial nerve stimuli and resultant signals. In particular, in order to measure many brain signals at several portions simultaneously and minimize the damage of neurons, an MEMS cranial neural probe with a small size where several electrodes are integrated has been developed. However, since conventional MEMS probes are mostly made of rigid silicon entirely, the probes consistently apply stimuli to the brain after being inserted into the brain causing continued damage. Since the body where the probe is connected is fixed to the outside of the brain and the probe is inserted into the flexible brain, when the brain breathes or an experimental subject where the probe is inserted into the brain moves, the brain also moves and accordingly the probe consistently stimulates the flexible brain.
However, since conventional MEMS probes are mostly made of rigid silicon entirely, the probes consistently apply stimuli to the brain after being inserted into the brain to remain damages. Since the body where the probe is connected is fixed to the outside of the brain and the probe is inserted into the flexible brain, when the brain breathes or an experimental subject where the probe is inserted into the brain moves, the brain also moves and accordingly the probe consistently stimulates the flexible brain.
In order to solve the above problem, it has been attempted to make the probe with flexible material. However, if the probe is made of flexible material, the probe should have a great thickness or be reinforced with a structure for insertion in order to maintain the intensity when the probe is inserted, and so the brain damage at the insertion of the probe increases.
In this regard, US Unexamined Patent Publication No. 2011/0144471 discloses a probe made of flexible material, where the probe should be inserted by making the probe with a great thickness or using an inserting device when the probe is inserted for the in-vivo test. Therefore, when the probe is inserted, the brain damage increases.
The thesis “Fabrication and characterization of the flexible neural microprobes with improved structural design” is directed to decreasing the damage at the insertion into the brain by making a probe with flexible material. However, the micro probe of the above paper has a metallic layer interposed between flexible polyimide layers in order to maintain the insertion intensity, and so the entire thickness of the probe increases, and its manufacturing process is complicated.
In addition, the thesis “A flexible fish-bone-shaped neural probe strengthened by biodegradable silk coating for enhanced biocompatibility” discloses that the entire probe is coated with silk which can be dissolved in the brain, in order to maintain the insertion intensity of the probe made of flexible material. However, in this case, the entire thickness of the probe increases, which generates great brain damage at insertion, and in case where the silk inserted into the brain is not completely dissolved, the silk may cover the electrode and disturb recording of neural signals.